Friedrich Frey

TL;DR: In this article, the crystallographic and microstructural parameters of pure zirconia powders were studied by X-ray and neutron powder diffraction, and a significant influence of the flow rate of quenching gas on the phase composition (the tetragonal to monoclinic ratio varied between 0.6 and 3.5) and on the micro-structure was observed, while structural parameters of both phases of all investigated samples remained essentially unchanged and were close to those reported in the literature.

TL;DR: In this paper, the average defect structure of congruent lithium niobate has been reexamined by X-ray and neutron powder diffraction, and the Rietveld refinements show that the Li-site vacancy model [Li 1 − 5 x Nb 5 x ][Nb 1 − 4 x □ 4 x ]NbO 3 in which the Nb site is fully occupied describes best the average defects.

TL;DR: A comparative study of tetragonal (Y-TZP, 3 mol% Y 2 O 3 ) and cubic (CSZ, 15 mol% CaO) zirconia powder samples was carried out to learn about a possible structural origin of the superior ionic conductivity of TZP at low temperatures.

TL;DR: In this article, the structural changes due to the penetration of water radicals during hydrolysis are discussed, which give rise to stresses which then have an impact on the energy balance between the tetragonal and the monoclinic phase (martensitic transformations).

TL;DR: Extensive neutron diffraction and Rietveld studies of dense, hot pressed mullite (3Al 2 O 3 ·2SiO 2 ) have been conducted up to 1650°C in air, yielding a complete set of lattice parameters and axial thermal expansion coefficients as discussed by the authors.